1. Field of the Invention
This invention relates to enhanced recovery from a well. More specifically, this invention relates to an improved apparatus that enhances recovery in oil and gas wells by employing regulated flow devices and techniques and optionally in combination the addition of fluid enhancing additives.
2. Related Art
As was discussed in applicant's application U.S. Ser. No. 09/057,039, each well has its own predetermined optimal recovery conditions which are determined by the natural geological formation of the well. When a successful well is drilled, there is commonly enough gas-volume to fluid-ratio and bottom hole pressure to create a natural flow from the well. This ability to flow at a certain velocity to insure fluids are lifted is termed "critical flow rate." The ability to substantially maintain or simulate natural flow conditions is critical in optimizing recovery.
Under the natural flow pressure, fluid flow is created by virtue of the liquid being broken up into small units by gas existing therein and is carried to the surface due to a fluid "lightening" effect under gaseous expansion to achieve critical flow rate. The combined gas and liquid are transferred via an upstream flow line to a fluid/gas separator which is designed to remove the liquid into storage tanks and remove the gas to a downstream sales flow line which commonly connects with a utility service provider at what is more commonly referred to as the pipeline.
Unfortunately, in new tight gas sand wells or older wells having reduced reserve volumes, and pressure in the well depletes during the flow cycle and negatively impacts the optimal recovery conditions and flow needed to achieve critical flow rates. As a result, typically only part of the oil and gas contained in the underground formation by a primary recovery method which uses the natural flow force present in the reservoir is possible. A variety of enhanced recovery techniques such as artificial lift systems, so-called secondary or tertiary recovery methods, have been employed to increase the recovery of oil and gas from subterranean reservoirs.
A common artificial lift, secondary recovery method includes a combination of shutting in the well for a period of time to allow for pressure build up and allowing a plunger to drop to the bottom of the well and then opening the well causing the plunger to drive the fluid to the surface. Another such enhanced recovery technique is to use a pump truck to pump additives into the oil well-bore. These additives can, for example, reduce scale, paraffine and the viscosity of the oil and increase production of oil recovery.
A problem with these prior techniques is the lack of proper control in order to carry out those techniques during initiation and slow down of flow within a well. Also, waste can occur downstream in that metering devices of service providers to which the downstream sales flow line connects do not properly meter or record spikes (temporary large amounts of gas over that recordable by the meter) which occur during the other recovery methods. In this regard, care must be taken to maintain optimal recovery conditions in carrying out other recovery methods.
Applicant's prior said application is directed at solving a significant part of the aforementioned problems by providing an apparatus which controls the flow within the downstream sales line. There remains a need to improve upon enhancing oil and gas recovery techniques such as those of the present invention.